'Dog house' insulation...anyone done this?

[Rocky_Road]

I see where Bayliner is bragging that their 2009 bow rider line, has sound insulation in their engine box covers (dog house).

Not a bad idea...has anyone ever done this to their engine cover?

Seems simple enough. Just need to figure out what would work the best, and be flexible enough to conform to the inside configuration...not too thick, and easily 'glued' into place.

Any idea how Bayliner is doing this...?

 

[mphy98]

Re: 'Dog house' insulation...anyone done this?

on last boat with a HP Chrysler, the insulation was ruined by mice and critters. i used automotive type, silver on both sides, available everywhere. very quiet and very easy to install. will do it to the new boat doghouse as well.

 

[oops!]

Re: 'Dog house' insulation...anyone done this?

dont know what b-liner is using.....but sound in boats is a major problem....i did my doghouse with everything......finally i used a automotive insulator.....silver foil on one side and a cloth like stuff on the other....it worked ok....

on the new configuration im doing everything.....dynamatt....the auto insulation and a few other tricks.....i dont want to hear the motor at all unless its at wot!

 

[Bob_VT]

Re: 'Dog house' insulation...anyone done this?

Closed cell foam covered with foil, automotive sound insulation, rammat, dynomat...... it all costs money.

Just keep in mind that the heat and amount of flammable stuff in the doghouse can have a big impact on how fast a fire spreads too!

 

[Rocky_Road]

Re: 'Dog house' insulation...anyone done this?

Closed cell foam covered with foil, automotive sound insulation, rammat, dynomat...... it all costs money.

Just keep in mind that the heat and amount of flammable stuff in the doghouse can have a big impact on how fast a fire spreads too!

Good point...are you saying that the above items, will retain heat in the engine compartment? To the point that the air circulating around the engine, will be higher than normal?

If so...I will rethink this one...!

 

[strokeoluck]

Re: 'Dog house' insulation...anyone done this?

Closed cell foam covered with foil, automotive sound insulation, rammat, dynomat...... it all costs money.

Just keep in mind that the heat and amount of flammable stuff in the doghouse can have a big impact on how fast a fire spreads too!

I'm not an engineer, therefore certainly not an automotive engineer, but I spent a number of years in Michigan visiting auto plants and hanging out w/auto guys. My recollection on automotive sound insulation in vehicles is that it's primarily distributed around the passenger compartment, not the engine compartment. No? If that's accurate I too would be nervous about putting too much of it around the boat engine. I know they like to cram it in plenty of areas behind the firewall, underneath wheel wells, etc. But I've never seen bunches of it directly in the engine compartment.

In theory I love the idea. Perhaps there is an auto engineer or two that could comment on the idea?

 

[Silvertip]

Re: 'Dog house' insulation...anyone done this?

You can insulate the be-jeepers out of a box but if there are any holes in it the sound will still get out. For proper engine performance there MUST be airflow into and out of the engine bay, so those openings will still allow noise to escape. The materials being recommended will work to a degree but they will not make a silent drive system.

 

[Bondo]

Re: 'Dog house' insulation...anyone done this?

Closed cell foam covered with foil, automotive sound insulation, rammat, dynomat...... it all costs money.

Nope,.... Not really....

When I went from an I4 to a V6,.. I had to build a New motorbox....
We built it out of PT plywood, fitting as Tightly as we could get it...

1st, I lined the Outside of it with closed cell foam, then covered that with vinyl...
Next I used the same closed cell foam,+ vinyl to make curtains to cover the areas to the port,+ starboard sides...
Then I flipped the motorbox,+ stapled the closed cell foam All over the inside of the box....

The Vinyl I used was bought as a close-out sale, of Nato tent material,..Olive drab on 1 side,+ battleship grey on the other,...
I put it all on with the grey side out... Paid about $3. or $4.00 a yard...

The Closed Cell Foam,....
It came out of Dumpsters,... Closed cell Packing foam...Found the Right dumpster,+ got Miles of the stuff....

This all happened in 98, or 99,+ it's Still holding up Very Well...

 

[a70eliminator]

Re: 'Dog house' insulation...anyone done this?

my 1990 Chaparral i/o has an isulated engine cover from the factory, as does the cover on my 1967 Evinrude outboard, I thought they all did but I guess not. The insulation looks sorta like thin foam on both, it's black on the Chappy and on the evenrude it's tan colored, but pretty much the same material.

 

[Rocky_Road]

Re: 'Dog house' insulation...anyone done this?

Thanks, everyone!

If I put my 'thinking' cap on...and consider the above suggestions...here is where I end up:

The aluminum faced sound retarding stuff (eg. Dynomat), will quiet the engine bay.

But...there has to be some additional heat trapped in the engine area, and that wouldn't be good in the hot summer days.

Project scrapped...unless there is some sort of sprayed on barrier, that will not reflect the heat back onto the engine. Cars used to be undercoated, by the dealers, but no longer...probably due to the added weight.

 

[lowkee]

Re: 'Dog house' insulation...anyone done this?

I recently looked at some new IO boats for ideas on an interior of mine, since I plan on building it from scratch. What I found in the engine compartment was eggcrate foam! It was obviously not the cheap crap you put on your bed, but it was definitely foam and not covered with any reflector. Just dark grey eggcrate foam glued to all inner walls, including the top.

And Bond-o, I really need to find the dumpsters you used! I'm going to need some serious foam seat cushioning soon, and man is that stuff pricey!

 

[Mark_VTfisherman]

Re: 'Dog house' insulation...anyone done this?

i used automotive type, silver on both sides, available everywhere. very quiet and very easy to install.

This used to be available as a fire-retardant product and I even outboards have some stuff like it glued to the motor shroud.

That is my suggestion. It will dampen a lot of sound.

 

[a70eliminator]

Re: 'Dog house' insulation...anyone done this?

Heat removed from a raw water cooled i/o engine is dispated into the lake via exhaust manifolds, are you in effect saying the doghouse is a big heat sink and helps cool the engine compartment therfore shouldn't be insulated? if so wouldn't you think the doghouse would have cooling vents somewhere to let the heat out?
Insulated or not I don't think it would effect the engine's running temp.

 

[JorgeE]

Re: 'Dog house' insulation...anyone done this?

Guys,
Some thoughts on the materials and heat retention...
- Normal boat engine boxes are made of wood, covered with vinyl, foam, etc. Even just the wood would insulate (heat) already. Additional foam will have small effect, Foam in there will simply absorb and disipate noise
- Much of the heat on auto engines comes from the exhaust manufolds, turbos, EGR systems, and of course radiation and AC condenser. Boats manifolds give off MUCH less heat due to water cooling, no EGR systems, no radiator and AC condenser - sum of these is much less heat being given off.
- Noise is also transmitted, not just radiated, through the motor mounts. Auto mounts are soft and pliable to isolate vibrations from frame; Marine mounts are stiff and will transmit vibrations (noise) to hull.
Insulation on cars is everywhere... laminated oil pans and valve covers, strategically reinforced blocks in just the right places, as well as in the firewall and interior. We can't do the same things to boats...
I think we can make our boats quieter, but that we won't be able to get them to the level of a car.
Make the box think and stiff, seal it as well as possible, and let the vents vent, with no paths to cockpit are, and remember that engines make sound, noise is only the part we don't like.
Have fun!
Jorge

 

[country_bumpkin]

Re: 'Dog house' insulation...anyone done this?

Thanks, everyone!

If I put my 'thinking' cap on...and consider the above suggestions...here is where I end up:

The aluminum faced sound retarding stuff (eg. Dynomat), will quiet the engine bay.

But...there has to be some additional heat trapped in the engine area, and that wouldn't be good in the hot summer days.

Project scrapped...unless there is some sort of sprayed on barrier, that will not reflect the heat back onto the engine. Cars used to be undercoated, by the dealers, but no longer...probably due to the added weight.

Shouldn't you be running your blower? If you are I don't think that any excess heat will buildup in your engine compartment. Even without the blower I doubt that sound insulation would let heat build up, air is sucked into the compartment to feed the engine, right?

 

[country_bumpkin]

Re: 'Dog house' insulation...anyone done this?

Heat removed from a raw water cooled i/o engine is dispated into the lake via exhaust manifolds, are you in effect saying the doghouse is a big heat sink and helps cool the engine compartment therfore shouldn't be insulated? if so wouldn't you think the doghouse would have cooling vents somewhere to let the heat out?
Insulated or not I don't think it would effect the engine's running temp.

sorry didn't read this, but another good point about excess heat. I agree

 

[Rocky_Road]

Re: 'Dog house' insulation...anyone done this?

I recently looked at some new IO boats for ideas on an interior of mine, since I plan on building it from scratch. What I found in the engine compartment was eggcrate foam! It was obviously not the cheap crap you put on your bed, but it was definitely foam and not covered with any reflector. Just dark grey eggcrate foam glued to all inner walls, including the top.

And Bond-o, I really need to find the dumpsters you used! I'm going to need some serious foam seat cushioning soon, and man is that stuff pricey!

This makes sense to me...no metal barrier to trap the heat.

 

[Rocky_Road]

Re: 'Dog house' insulation...anyone done this?

Guys,
Some thoughts on the materials and heat retention...
- Normal boat engine boxes are made of wood, covered with vinyl, foam, etc. Even just the wood would insulate (heat) already. Additional foam will have small effect, Foam in there will simply absorb and disipate noise
- Much of the heat on auto engines comes from the exhaust manufolds, turbos, EGR systems, and of course radiation and AC condenser. Boats manifolds give off MUCH less heat due to water cooling, no EGR systems, no radiator and AC condenser - sum of these is much less heat being given off.
- Noise is also transmitted, not just radiated, through the motor mounts. Auto mounts are soft and pliable to isolate vibrations from frame; Marine mounts are stiff and will transmit vibrations (noise) to hull.
Insulation on cars is everywhere... laminated oil pans and valve covers, strategically reinforced blocks in just the right places, as well as in the firewall and interior. We can't do the same things to boats...
I think we can make our boats quieter, but that we won't be able to get them to the level of a car.
Make the box think and stiff, seal it as well as possible, and let the vents vent, with no paths to cockpit are, and remember that engines make sound, noise is only the part we don't like.
Have fun!
Jorge

My 'box' is fiberglass...and that translates to a very thin barrier, between the engine bay, and the interior of my boat!

If Bayliner decided that it was a 'plus' to sound insulate the dog house...there has to be some logic being applied here.

My reservation is solely about the metallic barrier that goes with the audio sound barriers.

There is no way that some of the engine heat is not currently being dissapated through my thin box cover...I would rather have the noise level, over any engine bay temperature increase.

I need to see how Bayliner is doing this...might be worth buying a new cover!

 

[Bondo]

Re: 'Dog house' insulation...anyone done this?

And Bond-o, I really need to find the dumpsters you used! I'm going to need some serious foam seat cushioning soon, and man is that stuff pricey!

Ayuh,...

Jobsite Dumpsters,... Near the end of the job, things like furniture,+ fixtures are packed with the stuff,...
Usually all ya gotta do is Ask,.... I've Never heard a No...

 

[projecthog]

Re: 'Dog house' insulation...anyone done this?

My 'box' is fiberglass...and that translates to a very thin barrier, between the engine bay, and the interior of my boat!

If Bayliner decided that it was a 'plus' to sound insulate the dog house...there has to be some logic being applied here.

My reservation is solely about the metallic barrier that goes with the audio sound barriers.

There is no way that some of the engine heat is not currently being dissapated through my thin box cover...I would rather have the noise level, over any engine bay temperature increase.

I need to see how Bayliner is doing this...might be worth buying a new cover!

I am willing to bet that if you run your engine up to operating temperature and take a reading of the engine compartment, you will not see a significant increase in temperature after adding any insulation.

The engine is thermostatically regulated for a range of internal operating temperatures, and will not or should not have a differential of more than maybe 30 or 40 degrees max between idle and WOT.
Most of the heat created therefore will be caused by the increased temperature of the block when running harder and not by the exhaust because it is shielded by water that boils at 212 degrees and even that's not hot enough to set things on fire.

It is different in cars where there is no water cooled shielded exhaust and where the heat is passed off through the walls of the exhaust manifolds and pipes, carried off by air flow through the compartment and out the bottom.

If this were the case in an I/O situation in a boat, then on some boats the rubber exhaust hoses would burn off or the engine cover would heat up and catch on fire very quickly as air flow, other than that of the bilge blower system, is near nonexsistent in the engine box.

Relying on my modest experience in engine rooms on ships, the temperatures there do not "normally" rise above 110 dergrees either as far as I know, even with the air conditioners off. There the engine box is just a bit bigger so you can stand in it.

If there is ample room to install any kind of fuel proof and flame retardant sound proofing without touching any engine parts, there should not be any issues.
I would worry more about the fuel and oil resistance of the stuff you are going to use than the heat affective value.

PH.